Draw press



2 Sheets-Sheet l O. KUHNER DRAW PRESS Filed May 20, 1936 Sept. 13, 1938.

Sept. 13, 1938. o. KUHNER DRAW PRESS Filed May 20, 1936 2 Sheets-Sheet 2HTT'OQIVEY Patented Sept. 13, 1938 UNITED STATES PATENT OFFICE 10Claims.

This invention relates to improvements in hydraulic draw presses whichare used for the production of hollow bodies from sheet metal plates.

In such presses the plates or sheets are clamped over a table adapted tobe moved hydraulically. On the table is secured the pattern, for examplea wooden pattern necessary for the production of the hollow body. Bymovement of the table against the clamped metal sheet the pattern isforced into it.

With patterns which do not have a simple form but show, for example, aplurality of curves or any other unusual form, it is not possible toclamp the sheet so that it bears throughout on the pattern. The drawingprocess does not then begin uniformly over the whole pattern. During theprocess the portions at which greater stretching occurs conform to thepattern more strongly and sharply than the portions subjected to lesserstretching. Moreover, these differences have to be equalized and it isnecessary first to work the portions of lesser stretching, for examplethe fiat portions, and then, by adjustment of the form, the portionssubjected to greater clamping. Formerly this was efiected by theinterposing of liners between the table and the pattern, thisnecessitating a very correct working of the liners.

' The invention consists essentially in that the table is arrangedmovable in space and fixable and that the clamping device consists ofblocks mutually adjustable individually or in groups, which blockscarearranged either on opposite sides only or on all sides of the table.With such the table without special liners being necessary. In this waythe use of such presses is simplified and the possibility of their useextended.

Moreover, the construction of the clamping device accord ng to theinvention serves to overcome the difficulties which arise during drawingwith complicated patterns. For example, the new construction of clampingdevice enables desired form of curve. Re-clamping, that is to say asecond working process, or patterns with exchangeable parts are nolonger necessary.

.The constructional form of the clamping device and the table accordingto the invention may be as desired, but the following more fullydescribed forms are particularly advantageous. Each section or block ofthe clamping device is secured by one or more bolts to the base plate,which is likewise adjustable in a known mana construction of press thepattern can be brought to any desired position by adjustment of clampingof the sheet to be obtained along any ner. The bolts are guided in slotsin the blocks, which themselves lie on the base plate either adjustablein plane surfaces or swingable in' cylindrical surfaces.

The adjustability of the table is attained in a simple way by supportingit at at least three points and connecting the table by ball and socketjoint with a hydraulically operated ram. The table can, however, also bemoved by carrying it on two or more independently'operating hydraulicpistons. Thus, if the centres of the pistons lie in one plane, aswinging movement about parallel axes is possible. With otherarrangements of the piston centres, the table can be adjusted stillfurther. The table can be adjusted in any desired direction, if it isadjustably supported at at least three points, and a ram carried by twoor more pistons serves as the supporting device. This arrangement offersa possibility f double adjustment for firstly the ram can be adjusted asdesired and on the other hand the table, which is supported against theram, is adjustable in any direction relatively to the latter.

Some embodiments of the invention are lustrated in the accompanyingdrawings by way f example, in which:

Fig. 1.is an elevation of a draw press.

Fig. 2 is a plan view thereof.

Fig. 3 is a side elevation of Fi 1.

Fig.4 is a part sectional elevation of a modified form of table. a

' Figs. 5 and 6 are an elevation and plan view respectively of aclamping device in accordance with the invention, and

Fig. '7 is an elevation of a modified form of clamping device.

In the draw press according to Figs. 1.3, two base plates 2 and 3 reston three supports I. The base plates 2 and 3 are relatively adjustableand fixable in the direction of the transverse axis of a plate 4 andcarry along their sides the clamping blocks 5 and 6, which, showndiagrammatically only in Fig. 2. are adjustable on the base plates 2 and3 in' grooves I and B respectively; The plate 4 is carried by a piston 9which reciprocates in a cylinder l0 under the action of water pressurein known manner. The plate 4 is, moreover, formed with a ball seat inwhich a ball I I rests. The latter is secured to the actual press table[2 on which the pattern l3 rests. The table l2, moreover, is supportedagainst the plate 4 by three adjustable bolts I 4. In Fig. 1 the pressis illustrated, with the table [2 not adjusted, at the end of a workingstroke, the stretched workpiece l5 being omitted. The latter is shown inthe clamping blocks 6 have been omitted. At

the commencement of the working operation the metal sheet is clamped inthe bloclns 5, whereupon the piston 9, plate 4, table 12 and pattern l3are forced upwardly against the workpiece I5, which takes the form ofthe pattern I3. In Fig. 2 the blocks 5 are relatively displaced andlikewise the blocks 6 can take a difierent relative position. Thearrangement of these blocks 6 enables the workpiece to be clamped notonly at opposite sides but on all sides, or to be held only by means ofthe blocks 6 without, as was formerly necessary, the table l2 having tobe turned through 90 and the base plates 2 and 3 separated from oneanother.

The draw press according to Fig. 4 employs the same clamping devicesasthat according to Figs. 1 to 3, but the table I6 is adjustable in adifferent manner. The said table is pivotally mounted on three bearingsl1, l8 and IS, the bearing l8 being connected to a slide block 20, whichis guided in the straight guide 2| carried by supports 22. On the latterand also on supports 23 rest cylinders 24 in which pistons 25 slideunder the action of water pressure, the said pistons carryingdovetail-like bearings 26 in which slide members 21 carrying thebearings l1 and IS. The piston 25 is or both pistons are lifted foradjusting the table I6. During the actual drawing operation the table ispressed against the clamped sheet blank by further raising of one orboth pistons. Also in this case a pattern, not shown in Fig. 4, issecured to the table IS.

The two embodiments of the clamping device shown in Figs. 5-7 can beused in the presses according to Figs. 1-3 and 4. The clamping deviceaccording to Figs. 5 and 6 rests on the base plate and is moved thereonfor the purposes of adjustment, whilst the clamping device according toFig. 7 is guided, that is to say is swingable in a cylindrical surface.

The arrangements according to Figs. 5 and 6 consist of a block 28 onwhich are arranged two eyes 29 having slots 30 therein in which areguided the bolts 3| for securing the block 28. The edge of the sheet tobe treated is clamped between a swingable plate 32 and a projection 33of the block 28. The pivot pins 34 of the plate 32 rest in plates 35.The plate 32 is adjustable by means of a lever 36 fixed to the plate 32and movable in a slot 31 of the block 28. Raising the lever opens theclamping device and depressing closes it. This arrangement can also besecured in a simplified construction with only one bolt 3|.

The clamping device shown in Fig. 7 besides being adjustable on the baseplate 38 is swingable in the cylindrical surface 39. The under part 40is held against the base plate 38 by a bolt 4|, whilst the upper part 42is held by a bolt 45 swingable at 43 in the under part 40 and carried inthe upper part 42 by a ball joint 44. The actual clamping device, viz.projection 46 and plate 41 are formed the same as in the arrangementaccording to Figs. 5 and 6.

I claim:

1. In a hydraulic draw press of thetype referred to, the sub-combinationof t a base; a ress table movable relatively to said base; means fortilting said press table and clamping devices for a sheet to be treated,said devices comprising a plurality of blocks secured to said base, saidblocks each comprising an under part having an upper concave surface,and an upper part having a convex surface movable over said concavesurface; and means for holding said upper part in engagement with saidunder part.

2. In a hydraulic drawpress of the type referred to, the sub-combinationof: a base; a press table movable relatively to said base; means fortilting said press table, said means comprising means for adjustablysupporting saidtable at at least three points; and clamping devices fora sheet to be treated, disposed around said table on said base.

3. In a hydraulic draw press of the type referred to, thesub-combination of a base; clamping devices on said base; a press table;means for tilting said press table, said means comprising adjustablesupports for said table; a ball carried by said table; a second tablesupporting said press table by means of said supports and said ball; andmeans for operating said second table.

4 In a hydraulic draw press of the type referred to, the sub-combinationof a base; a press table; means for tilting said press table, said meanscomprising a cylinder carried by said base adjacent each end of saidtable and a piston movable in each of said cylinders for moving saidtable.

5. In a hydraulic draw press of the type referred to, the combinationof: abase; a press table; means for tilting said table, said meanscomprising adjustable supports for said table, a ball carried by saidtable, a cylinder; and a piston in said cylinder, said piston having abearing surface adapted to support said ball; hydraulic means foractuating said piston to move said table; a

clamping devices for a sheet to be treated, said devices comprising aplurality of blocks secured to said base, said blocks each comprising anunder part having an upper concave surface, and an upper part having aconvex surface movable over said concave surface; and means for holdingsaid upper part in engagement with said under part.

6. In a hydraulic draw press of the type referred to, the combinationof: a base; a press table; means for tilting said table, said meanscomprising adjustable supports for said table: a ball carried by saidtable, a cylinder, a piston in said cylinder, said piston having abearing surface adapted to support said ball; and hydraulic means foractuating said piston to tiltsaid table; and clamping devices for asheet to be treated disposed around said table.

7. In a hydraulic draw press of the type referred to, thesub-combination of: a base; a press table movable relatively to saidbase; means for tilting said press table; and a plurality of clampingdevices for a sheet to be treated upon said base, disposed on each sideof said table, each of said clamp devices being adjustable and securableindependently of each other of said devices, whereby said sheet may beclamped on opposite sides or on all sides of said table.

8. In a hydraulic draw press of the type re ferred to, thesub-combination of a base; a press table; a centrally disposed pivotbearing for said table; means for tilting said press table, said meanscomprising a cylinder carried by said base adjacent each end of saidtable and a piston movable in each of said cylinders to tilt said table.

9. In a hydraulic press of the type referred to, the sub-combination ofa base; a press table; a centrally disposed pivot bearing for saidtable; and means for tilting said press table, said means comprising acylinder carried by said base adjacent each end of'said table, apistonmovable said pistons independently of one another to tilt the saidtableas required. I

10. In a hydraulic press for the production of hollow bodies from sheetmetal plates, the subcombination of: a base; a press table disposedabove said base; and said table being movable relatively to said base; apattern necessary for the production 0!. the hoilombody carried on theupper face of said table remote from said base and over which a sheet tobe treated is stretched; clamping devices for said sheet disposed aroundsaid table on said base; and means for tilting said 5 press table andpattern.

A o'rro KtiHNER.

